The following invention relates to a clot filter and more specifically to an improved vena cava clot filter.
Vena cava clot filters are implantable devices positioned in the inferior vena cava. They are used to filter peripheral venous blood clots, which if remaining in the blood stream can migrate and cause harm. Although problems with such blood clots may not be chronic, most presently used vena cava filters are permanently implanted in the inferior vena cava and remain there for the duration of the patient's life. The filters themselves can cause clots and thus the use of a non-removable filter can be dangerous. These filters are non-removable and are generally inserted via the femoral or jugular vein.
It is preferable to be able to remove a vena cava filter and removable vena cava filters are known in the art. These removable filters must be introduced using a large bore catheter, such as an 8-14 french catheter. Such large bore catheters in a vein present dangers such as bleeding and vein dissection.
A problem with currently existing filters is that in some patients, where there is a very diffuse deep vein clot or thrombosis, large showers of clot can completely occlude the filter or force the filter out of position.
Presently known, vena cava filters are complex in design and expensive to manufacture.
Accordingly, it is an object of the present invention to provide a non-permanent vena cava filter that is introducible through a relatively small bore catheter.
Another object of the present invention to provide such a filter that will allow clots, of a certain size, to pass through the filter thereby lessening the possibility of having the filter occluded or forced out of position.
Still a further object of the present invention is to provide such a filter which is relatively simple in design and is relatively inexpensive to manufacture.